The present invention is concerned with a composition containing an antibiotic and a synthetic resin material and with the use thereof especially in surgery.
It is known that antibiotics, especially gentamycin, are slowly liberated from synthetic resins based on polymethacrylates and/or polyacrylates. A sharp initial drop in concentration, due to the liberation of the antibiotic from the outermost layers of the synthetic resin, is followed by an almost constant rate of liberation which, however, decreases slowly over a long period of time. These antibiotic-containing synthetic resins have hitherto been used as bone cements for fixing endoprostheses, for example, total hip endoprostheses, and have been used during the changing of infected endoprostheses. For use in combating infection and for prophylaxis, the compositions are prepared by adding the antibiotic before complete polymerization of the synthetic resin. Furthermore, it is known that for this purpose, synthetic resin particles in the form of a granulate or of small spheroids with a particle diameter of 1 to 20 mm., are especially suitable as carrier materials for antibiotics.
Furthermore, it is known from German Patent Specification No. 2,511,122 that an antibiotic can be liberated from bone cement in comparatively high concentration when the bone cement additionally contains sodium chloride, potassium chloride, sodium bromide and/or potassium bromide. However, the use of these additional materials can cause problems since they have a cell-damaging effect. Therefore, for example, they are not to be used in surgery.
In addition, it has been shown that the liberation of the antibiotic from the synthetic resin particles does not take place in an optimum manner and can vary from one batch to another. Furthermore, in some production processes for such synthetic resin particles, temperatures can sometimes be reached at which some of the antibiotic can be decomposed. The destroyed amount is then no longer available for therapeutic purposes.